The valve mechanism of U.S. Pat. No. 3,913,327, entitled "Flow Sensitive Valve Mechanism" and issued October 21, 1975 in the name of the inventor of the invention herein disclosed and claimed provides the background for this invention. That disclosure provided a fluid flow sensitive valve member in a valve chamber between a pressurizing chamber and an outlet port of a master cylinder. A compensation port leading to a fluid reservoir also opened into the valve chamber.
The valve member had flow sensitive fins angularly positioned in the flow path of fluid flowing through the valve chamber. The valve member had a valve body with a guide pin extending upwardly from the body into the lower portion of the compensation port to maintain the value member in lateral position relative to the valve seat formed at the bottom of the compensation port. That seat could be engaged by the valve body to close off the compensation port when the valve was moved upwardly, and could be disengaged to open the compensation port when the valve was moved downwardly.
A first valve member flow sensitive fin, formed on the valve body, was positioned near the port to the pressurizing chamber and was angled so as to deflect the fluid downwardly when fluid pressurization in the pressurizing chamber occurred. The impact force of the fluid acting on the fin moved the valve member upwardly to close the compensation port. The fluid flowed under and around the valve member, passing into the outlet port and pressurizing the appropriate mechanism to be operated by the fluid pressure.
A second valve member flow sensitive fin, also formed on the valve body and parallel to the first fin, was positioned near the outlet port so that when the pressure was released, the fluid flowing back into the valve chamber from the outlet port impinged on the second fin, forcing the valve member downwardly and opening the compensation port. The returning fluid coming back through the outlet port flowed through the compensation port into the fluid reservoir and also past the valve member back into the pressurizing chamber. The valve member was made of a material having a specific gravity slightly greater than the specific gravity of the fluid used so that the assembly would be self-bleeding.